Rubber modified nylon composition

ABSTRACT

A polyamide composition of improved impact comprising a blend of components (A) 5 to 79.5 weight percent of a graft rubber composition of a graft polymer of methyl (meth)acrylate and/or (meth)acrylonitrile and a vinylaromatic monomer grafted onto a substrate rubber, (B) 94.5 to 20 weight percent of a polyamide resin, and (C) 0.5 to 60 weight percent of a polymer compatibilizer which contains from about 0.05 to 4.0 mole percent of a comonomer containing a functional group which reacts with the polyamide resin is useful for molding and extrusion.

This application is a continuation of Ser. No. 07/363,341 filed Jun. 2,1989 abandoned), which is a continuation of Ser. No. 07/132,234 filedDec. 14, 1987 (abandoned), which is a division of Ser. No. 06/842,338filed Mar. 21, 1986 (issued as U.S. Pat. No. 4,713,415), which is acontinuation-in-part of Ser. No. 06/733,560 filed May 10, 1985(abandoned).

This invention relates to thermoplastic polyamide compositions and moreparticularly to polyamide compositions having improved impactresistance.

Unmodified thermoplastic polyamides are generally regarded as havinggood elongation and good energy to break as demonstrated in tensiletests and high tensile impact strength and high energy absorption asdemonstrated in a falling dart test, e.g, the Gardner impact test.However, the polyamides are quite deficient in resistance to crackpropagation. This deficiency is reflected in notch sensitivity, brittlebreaks and occasional catastrophic failure of molded extruded parts. Thetendency of polyamides to break in a brittle rather than a ductilefashion is a significant limitation of their end use applications.

A variety of additives have been added to polyamides with someimprovement in toughness being obtained. Epstein (U.S. Pat. No.4,174,358) discloses a toughened multiphase thermoplastic compositionconsisting essentially of a polyamide matrix and at least one otherphase containing straight chain and branched chain polymers having aparticle size in the range of 0.01 to 1.0 micrometers which adhere tothe polyamide matrix resin and which also have tensile modulus in therange of about 1.0 to 20,000 psi (6.9 to 137,800 kPa).

Epstein has the disadvantage of requiring that its branched and straightchain polymers be functionalized to adhere to the polyamide matrix,thereby excluding the use of conventional polymers or rubbers which donot contain functional groups. In addition, the functionalization of thepolymers may result in cross-linking which results in poorprocessability properties if conditions are not properly controlled.

German Patent Publication DE3120-803 discloses thermoplastic polyamidemolding compositions comprising a polyamide, a graft rubber composition,styrene-acrylonitrile copolymer and a styrene copolymer with 2 to 50weight percent of carboxylic acid and/or anhydride groups. Suchcompositions provide some increase in Izod impact of a nyloncomposition, however, the improvements are less than can be achievedwith the present invention.

The present invention provides a polymeric composition and molded orextruded parts prepared from the composition comprising a blend ofcomponents:

(A) 5 to 79.5 weight percent of a graft rubber composition comprising agraft copolymer of from 15 to 85 parts by weight of a monomer selectedfrom the group consisting of C₁ to C₄ alkyl acrylates, C₁ to C₄ alkylmethacrylates, methacrylonitrile and acrylonitrile and from 85 to 15parts by weight of a vinylaromatic monomer, wherein the monomers arepolymerized in the presence of and grafted onto a rubber substratehaving a glass transition temperature below 0° C., wherein the weightpercentage of the rubber is in the range from 5 to 80 percent and theweight percentage of the graft copolymer is in the range of 95 to 20percent of the graft rubber composition;

(B) 94.5 to 20 weight percent of a polyamide resin; and

(C) 0.5 to 60 weight percent of a copolymer compatibilizer comprising acopolymerized functionalized monomer capable of reaction with thepolyamide resin, wherein the concentration of functional groups of thecopolymer is in the range of 0.05 to 4 mole percent. The percentageweights of components A, B and C are based on the total weight ofcomponents A, B and C in the blend. Preferably the amounts of componentsA, B and C are in the range of 20 to 79, 79 to 20 and 1 to 60 weightpercent, respectively, of the total weight of A, B and C.

Component A is typically an ABS or MBS type polymer, that is to say adiene rubber substrate grafted with a vinylaromatic monomer and eitheracrylonitrile, methacrylonitrile, a C₁ to C₄ alkyl methacrylate, a C₁ toC₄ alkyl acrylate or a mixture conventionally a diene rubber such aspolybutadiene, polymers of butadiene with a comonomer such as styrene oracrylonitrile which rubber contains at least 50 percent and preferablyat least 80 percent by weight of butadiene or a butadiene based block orradial-block rubber. However the rubber need not be a conventionalpolybutadiene or butadiene/styrene copolymer since any rubber with aglass transition temperature below 0° C. can be used. The glasstransition temperature is conveniently measured by differential thermalanalysis by heating a rubber sample under nitrogen at a rate of 10° C.per minute. Other rubbers such as EPDM rubber, polypentenamer,polyisoprene, polychloroprene, polyacrylate rubbers and the like can, ifdesired, also be used. Preferably polyacrylate rubbers contain a minoramount up to 5 weight percent of an interpolymerized monomer such asallyl acrylate to provide unsaturation and enhance grafting thereto.

Vinylaromatic monomers used for the graft copolymer of component Ainclude styrene, and substituted styrenes such as alpha-methyl styrene,chlorostyrene, bromostyrene, p-methyl styrene, and vinyl toluene. Theweight ratio of vinylaromatic monomer to comonomer in the graftcopolymer of component A is preferably in the range of 20:80 to 80:20and the weight percent of the rubber is in the range of 5 to 60 percentof the total weight of the graft rubber composition. When thevinylaromatic monomer is styrene and the comonomer is acrylonitrile, amore preferred weight ratio of styrene to acrylonitrile is in the rangeof 80:20 to 50:50. The ratio of comonomers of the graft copolymer ispreferably selected so that the ungrafted copolymer fraction has atensile modulus of at least 25,000 psi, more preferably at least 50,000psi. Advantageously graft polymerization conditions are selected toprovide a grafted copolymer fraction, i.e., graft efficiency of at least20 weight percent and preferably at least 40 weight percent of the totalcopolymer present in the graft rubber composition, and provided thegrafted copolymer fraction is maintained above 20 weight percent, thegraft copolymer may be diluted by addition of separately preparedcopolymer of vinyl aromatic monomer and comonomer selected from thegroup consisting of acrylonitrile, methacrylonitrile, C₁ to C₄ alkylacrylates and C₁ to C₄ alkyl methacrylates. Graft polymerizationconditions are advantageously selected to provide a copolymer of weightaverage molecular weight less than 200,000 and preferably less than150,000 measured on the ungrafted fraction by gel permeationchromatography as hereinafter described. The particle size of the rubbergraft composition is advantageously in the range of 0.05 to 1.0 microns,preferably 0.1 to 0.5 microns.

Component B is a polyamide such as nylon 6 or poly(caprolactam), nylon11 or poly(11-aminoundecanoic acid), nylon 12 or poly(lauryl lactam) orpoly(12-aminododecanoic acid), nylon 6,6 or poly(hexamethyleneadipamide), nylon 6,9 or poly(hexamethylene azelamide) orpoly(hexamethylene nonandiamide), nylon 6,10 or poly(hexamethylenesebacamide) or poly(hexamethylene decanediamide), nylon 6,12 orpoly(hexamethylene dodecanodiamide) or nylon 4 or poly(Y-butyrolactam),nylon 7 or poly(7-aminoheptanoic acid) or poly(7-aminooenanthylic acid),nylon 8 or poly(8-aminocaprylic acid) or poly(8-aminooctanoic acid),nylon 10,6 or poly(decamethylene adipamide) and numerous partiallyaromatic nylons (PARNs). PARNs result when an aromatic residue or unitis substituted in whole or in part for an aliphatic residue or unit inan aliphatic nylon polymer. For example, substitution of all of theadipic acid [HOOC--(CH₂)₄ --COOH] residues in nylon 6,6 by those frommixtures of about 30-60 percent terephthalic acid (TA, or p-HOOC--C₆ H₄--COOH)/70-40 percent isophthalic acid (IA, or m-HOOC-C₆ H₄ --COOH)gives suitable PARNs which are high-melting, partly crystalline nylons6,TA-co-6, IA or poly(hexamethylene tere-co-isophthalamides). Othersuitable PARNs are partly crystalline nylons 6,6 -co-6,-TA, nylons6,6-co-6,IA, nylons 6,6-co-6,-TA-co-6,IA, and other similar PARNs,including partly crystalline PARNs wherein some of the diamine residueshave aromatic character and those containing lactam residues, such asnylons 6-co-6,6-co-6,TA. The weight average molecular weight of thepolyamide is advantageously greater than 10,000 and is preferablygreater than 20,000.

Also suitable are various types of copolyamides, block copolymers, andgraft copolymers. The preferred polyamide resins are nylon 6, nylon 6,6and random copolymers of nylon 6,6 and nylon 6.

Polyamides are generally neither miscible nor compatible withhydrocarbon polymers such as polystyrene and ABS. In the generallyaccepted sense, two polymers are miscible when they form a single phase,solid solution. Miscibility of a blend of polymers may be confirmed by asingle Tg for the polyblend, measured by calorimetry or dynamicmechanical analysis, or by optical clarity of the polyblend. When twopolymers exhibit different Tgs or loss tangent peaks, they demonstrateimmiscibility by forming two phases in a blend, each of which retainsthe Tg or loss tangent peak of one of the pure components. Partiallymiscible blends exhibit shifted or broadened loss tangent peaks relativeto the individual pure components. When two polymers are compatible, amixture provides a stable blend possessing a useful balance ofmechanical properties exhibited especially by impact strength or tensileelongation to fail equal or superior to such properties for thecomponent which provides the continuous phase in the mixture. Bycontrast, when two polymers are incompatible, the mixture exhibitsgenerally poor mechanical properties, especially impact strength ortensile elongation to fail, which are lower than for the component whichprovides the continuous phase in the mixture. Incompatibility may bemanifested during processing, for example, molding and extrusion, byextensive phase separation resulting in layering of the polymers anddelamination under mild stress.

The present invention yields blends of polyamides and graft polymer ofthe ABS type that form compatible mixtures, i.e., stable mixturescomprising a micro dispersion of a minor amount of one polymer in acontinuous phase of a major amount of the other and results in polymerblends of generally improved balance of mechanical properties especiallytoughness demonstrated by higher impact strength and elongation to fail.When about equal amounts of polyamide and ABS are blended, uniformlyinterspersed coextensive phases are formed in the mixture which alsopossesses generally improved, mechanical properties. Such compatibleblends of polyamides and grafted rubbers, such as ABS, are obtained bythe use of the C component which acts as a compatibilizing polymer or"compatibilizer."

In the present invention, the structure of the C componentcompatibilizer is such that it meets several criteria:

1. the compatibilizer is at least partially miscible and preferablyfully miscible with the graft copolymer of the grafted rubber componentA;

2. the compatibilizer contains functional groups capable of reactingwith the amine or acid end groups of the polyamide. An example is theanhydride-amine reaction that occurs when maleic anhydride is present asa copolymerized portion of the compatibilizer molecule and reacts withthe terminal amine group in the polyamide molecule upon processing ofthe polymer blend;

3. the amount of reactive functionality in the compatibilizer is smalland is advantageously in the range of about one to ten functionalitiesper average compatibilizer molecule.

Component C is typically a copolymer of a vinylaromatic monomer of thetype in component A copolymerized with either acrylonitrile,methacrylonitrile, C₁ to C₄ alkyl methacrylate, C₁ to C₄ alkyl acrylateor a mixture of these monomers in a weight ratio of vinylaromaticmonomer to comonomer in the range of 85:15 to 15:85. Advantageouslycomponent C has a number average molecular weight of at least about21,000 and preferably at least about 30,000 and a weight averagemolecular weight of at least about 40,000 and preferably at least about60,000. The molecular weights are conveniently measured by gelpermeation chromatography as described hereinafter. While in principlethe molecular weight can be extremely high, it is advantageous to have aweight average less than 200,000 to provide ease of processing andblending with the other components of the polyblend and preferably lessthan 100,000. Component C contains from about 0.05 to about 4.0 molepercent of a copolymerized comonomer containing a functional group whichreacts with the amine or carboxylic acid groups of the polyamide andpreferably from about 0.1 to about 3 mole percent, preferably selectedto provide a concentration of functional group in the range of 1 to 10functional groups per average molecule of component C. The vinylaromaticpolymer may be functionalized by polymerizing the vinyl-aromatic monomerwith monomers containing a carboxylic acid such as acrylic ormethacrylic acid or C₁ to C₁₂ monalkyl esters of diacids such asmonomethyl maleate and mono-dodecyl fumarate, a dicarboxylic acid suchas fumaric acid, maleic acid, itaconic acid, aconitic acid or citraconicacid, an anhydride, such as maleic, itaconic, aconitic or citraconicanhydride, or with an epoxide such as glycidyl acrylate, glycidylmethacrylate or allyl glycidyl ether or other monomers containingsimilar functional groups. The preferred component C is a terpolymercontaining styrene, α-methylstyrene or p-methylstyrene, acrylonitrileand from about 0.1 to about 3.0 mole percent maleic anhydride. With sucha terpolymer miscibility with the graft copolymer of the rubber graftcomponent A is obtained when the graft copolymer also comprises styrene,α-methyl styrene or p-methyl styrene and acrylonitrile and the weightpercentage of the styrene monomer in the graft copolymer differs fromthe weight percentage of styrene monomer in component C by no more than±5 units. Preferably the same styrene monomer is selected for terpolymerC and the graft copolymer of component A. A more preferred component Cis a styrene-acrylonitrile-maleic anhydride terpolymer containing fromabout 0.3 to about 1.5 mole percent maleic anhydride and the mostpreferred contains about 1 mole percent maleic anhydride. The styrenemonomer:acrylonitrile weight ratio in component C is in the range of85:15 to 15:85 and is preferably in the range of 80:20 to 50:50.

The preferred amount of component C in the polyblend is in the.range of1 to 20 weight percent. A more preferred amount of component C in thepolyblend is in the range of 4 to 12 weight percent and even morepreferred is the range of 6 to 10 weight percent.

In addition to the above components the polyblends of the invention canadvantageously contain other additives such as plasticizers,antioxidants, stabilizers, flame-retardants, fibers, mineral fibers,mineral fillers, dyes, pigments and the like.

The components of the polyblend can be blended together by anyconvenient process. Usually however they are extrusion blended orcompounded in a high intensity blender such as a Banbury Mixer.

The invention is now described with reference to the following exampleswhich are for the purposes of illustration only and are not intended toimply any limitation on the scope of the invention. The componentsdescribed below are blended in a number of different ratios and testedfor various properties.

COMPONENTS USED

ABS-1 - prepared by the graft emulsion polymerization of styrene andacrylonitrile in a weight ratio of 70:30 in the presence ofpolybutadiene. ABS-1 contains 40 percent by weight of polybutadiene. Theweight average molecular weight of the ungrafted SAN polymer fractiondetermined on several different batches of the styrene/acrylonitrilegraft polymer by gel permeation chromatography (GPC) is in the rangefrom 75,000 to 150,000. ASTM Method D 3536-76 is used in GPC, modifiedin that four columns in series using micro Styragel™ (a trademark ofWaters Assoc.) packing are used with a nominal exclusion limit of 5,000nm, 10,000 nm, 100,000 nm and 1,000,000 nm. The detector is anultraviolet light detector set at wavelength 254 nm. The test samplesare prepared at a concentration of 0.25 weight percent of polymer intetrahydrofuran. The sample injection size is 0.2 ml and a flow rate of2 ml/min. at ambient temperature is used.

The grafted polybutadiene has an average particle size in the range offrom 0.1 to 0.25 micrometer measured as a weight average particle sizediameter with centrifugal photosedimentometer (CPSM) by the publishedprocedure of Graves, M. J. et al "Size Analysis of Subsieve PowdersUsing a Centrifugal Photosedimentometer", British Chemical Engineering9:742-744 (1964). A Model 3000 Particle Size Analyzer from Martin SweetsCo., 3131 W. Market St., Louisville, KY is used.

The ABS polymer is recovered from the emulsion by conventionalcoagulation, filtration and washing.

ABS-2 is prepared by the graft emulsion polymerization of styrene andacrylonitrile in a weight ratio of 70:30 in the presence ofpolybutadiene-styrene (90:10) copolymer, and contains 60 percent byweight butadiene-styrene copolymer. The grafted copolymer has an averageparticle size in the range 0.37 to 0.43 micrometer as measured by CPSMas described above. The weight average molecular weight ofrepresentative batches is in the range of 75,000 to 150,000.

ABS-3--the same as ABS-1 except that the ratio of styrene toacrylonitrile is 45:55.

Nylon-1--a random copolymer of 85 weight percent nylon 6,6 polymer(poly[hexa-methylene adipamide]) and 15 weight percent nylon 6(polycaprolactam).

Nylon-2--a nylon 6,6 polymer.

Nylon-3--a nylon 6,9 polymer. The weight average molecular weights ofthe nylons are in the range of 30,000 to 34,000.

Terpolymer-1--a terpolymer is prepared by polymerizing a monomer mixtureto provide a polymer containing a weight ratio of styrene toacrylonitrile of about 2.1:1 and a varied amount of maleic anhydride.The weight average molecular weight is in the range from about 60,000 to100,000 measured by GPC as described above.

Terpolymer-2--a terpolymer prepared by polymerizing a monomer mixture ofstyrene, maleic anhydride and methyl methacrylate to produce acomposition in which the above monomers are in the weight ratio of72:22:6 respectively. The weight average molecular weight isapproximately 150,000.

SAN is prepared by polymerizing a monomer mixture of styrene andacrylonitrile to produce a SAN polymer having a weight ratio of 76:24.The weight average molecular weight is approximately 100,000.

WORKING EXAMPLES AND TEST RESULTS

In each example and control example, one percent Ethanox™ 330antioxidant, an alkylated phenol available from Ethyl Corporation, isadded based on the total weight of the sample.

Izod impact is measured according to ASTM D-256-56 with results given injoules/meter (J/m).

Flex Modulus is measured according to ASTM D-790-66. The sample is 0.635cm×1.27 cm with a span of 10.16 cm and a 1.27 cm per second cross-headrate. The results are given in megapascals (MPa).

Tensile Yield is measured according to ASTM D-638 with results given inmegapascals (MPa).

Multiaxial Inverted Dart Impact (IDI) is measured according to amodification of the test described in Society of Plastics EngineersNational Technical Conference "Plastics in Surface Transportation" Nov.12-14, 1974 Detroit, Mich., page 238. In the modified test, instead ofthe dart being attached to the slider and striking the sample, thesample holder is attached to the slider and strikes the instrumenteddart. The rotary potentiometer is not used. The instrumented dart usedis 1.27 cm in diameter, and the sample strikes the instrumented dart ata velocity of 111.76 m/min. The samples are injection molded into 7.62cm×10.16 cm×0.254 cm and then are cut into 3.81 cm×5.08 cm×0.254 cmpieces for testing. The results are given in joules (J).

The IDI energy to maximum (E_(max)) is the energy needed to achieve theyielding of a ductile sample. The energy to failure (E_(fail))represents the energy necessary to cause a failure of a sample. The testis run at room temperature and at -20° C. to determine the effect oftemperature on the performance of the polymer. The difference betweenE_(fail) and E_(max) indicates the ductility of the sample and thedifference increases with ductility.

The polymer blends of each example are physically blended by anextrusion process. This involves a preblending step of physically mixingthe ABS, terpolymer and antioxidant and feeding the mixture into aKillion extruder possessing a single stage mixing screw (3.8 cm indiameter by 68.6 cm long) which is rotated at from about 101 to about103 revolutions per minute (RPM). The rear zone of the extruder isheated to 254° C. with the middle and front zones heated to 260° C. Theextruder is connected to a die with a single 0.318 cm diameter orificethrough a 0.04 cm to 0.06 cm opening screen pack. The die is heated to254° C. The extruded material is passed through a water bath andpelletized by a Dayton pelletizer. The rate of extrusion is 4.55 kgs perhour.

The pelletized preblended material of each example is then physicallymixed with the nylon and the mixture fed into the Killion extruderwherein the extrusion process is repeated as described above, exceptthat the rate of extrusion is 7.26 kgs per hour. The pelletized blendedmaterial is then injection molded into specimen bars for testingaccording to the procedures as set forth above with the testing resultsconcurrently listed for each example in Tables 1 to 5. The injectionmolding is conducted using a 28.3 g Arburg™ 200 "S" allrounder moldingmachine available from Arburg Machinenfabrik in Wurttemburg, Germany,possessing a general purpose screw with a check ring and a straightthrough nozzle. The molding conditions are as follows:

    ______________________________________                                        1. Temperatures:   Rear Zone   260° C.                                                    Center Zone 260° C.                                                    Front Zone  260° C.                                                    Nozzle      260° C.                                                    Mold         43° C.                                 2. Screw Speed:    94 rpm                                                     3. Injection Rate: 1.3 seconds                                                4. Hold and Cooling Times:                                                                       25-35 seconds                                              5. Hydraulic Pressures:                                                                          Injection   5512 kPa                                                          Hold        4823 kPa                                                          Back         344 kPa                                       ______________________________________                                    

EXAMPLES 1 TO 4 AND CONTROLS 1 AND 2

Examples 1 to 4 and Controls 1 and 2, shown in Table 1, illustrate theeffect of varying the amount of maleic anhydride (MA) in the terpolymer.A sharp optimum in Izod is seen between 0.2 and 5.0 percent MA in theterpolymer. The maximum Izod is observed at 1.0 percent MA as seen inExample 3 which has a tensile yield of 40.87 MPa, a flex modulus of 1805MPa, an IDI E_(max) at 23° C. of 21.7J, E_(fail) at 23° C. of 41.8J,E_(max) at -20° C. of 26.0J and an E_(fail) at -20° C. of 44.0J, whichindicates a tough, ductile polymer.

EXAMPLES 5 TO 10 AND CONTROL 3

Examples 5 to 10 and Control 3, shown in Table 2, illustrate the effectof the amount of terpolymer in the blend on Izod performance.

EXAMPLES 11 TO 13 AND CONTROL 4

Examples 11 to 13 and Control 4, shown in Table 3, show that ABSpolymers with varying acrylonitrile content can be effectively used inthe present polyblend.

EXAMPLES 14 TO 17 AND CONTROL 5

Examples 14 to 17 and Control 5, given in Table 4, show that the nyloncontent of the polyblend can be lowered and still be effective to givean improvement in Izod.

EXAMPLES 18 TO 20

Examples 18 to 20 given in Table 5 show that a variety of nylons aresuitable for the present polyblends.

                  TABLE 1                                                         ______________________________________                                        EFFECT OF MA CONTENT IN TERPOLYMER                                            ON IMPACT STRENGTH OF POLYBLEND                                                                                Control                                                                              Control                                        Ex 1 Ex 2   Ex 3   Ex 4 1      2                                     ______________________________________                                        ABS-1       50     50     50   50  50     50                                  Terpolymer-1                                                                              6      6      6    6    6      6*                                 Nylon-1     44     44     44   44  44     44                                  mole % MA in                                                                              0.2    0.5    1.0  1.5   5.0  22                                  Terpolymer                                                                    Izod       125    591    851  466    50.4   53.1                              ______________________________________                                         *Terpolymer-2                                                            

                  TABLE 2                                                         ______________________________________                                        EFFECT OF VARYING AMOUNT OF TERPOLYMER                                        ON IMPACT STRENGTH OF POLYBLEND                                                      Control 3                                                                            Ex 5   Ex 6   Ex 7 Ex 8 Ex 9 Ex 10                              ______________________________________                                        ABS-1    50       50     50   50   50   50   50                               Terpolymer-1                                                                           0         1      3    6   10   15   20                               Nylon-1  50       49     47   44   40   35   30                               mole %   0         1      1    1    1    1    1                               MA in                                                                         Terpolymer                                                                    Izod     75.9     146    233  851  591  320  211                              ______________________________________                                    

                  TABLE 3                                                         ______________________________________                                        IMPACT STRENGTH OF POLYBLENDS CONTAINING                                      DIFFERENT ABS POLYMERS                                                                  Control 4                                                                            Ex 11     Ex 12   Ex 13                                      ______________________________________                                        ABS*        33       33        50    50                                       Terpolymer-1                                                                              0        4          10** 10                                       Nylon-1     63       63        40    40                                       SAN         4        0          0     0                                       mole % MA   0        1          1     1                                       in Terpolymer                                                                 ______________________________________                                        *ABS-Type                                                                             ABS-2   ABS-2   ABS-3 ABS-1                                           Izod    60.7    103.0   168   201                                             **The weight ratio of styrene to acrylonitrile is 0.43                    

                  TABLE 4                                                         ______________________________________                                        LOW NYLON BLENDS                                                              POLYBLENDS CONTAINING 20 WT. % NYLON                                                  Control 5                                                                            Ex 14    Ex 15   Ex 16  Ex 17                                  ______________________________________                                        ABS-1     80       74       70    65     60                                   Terpolymer-1                                                                             0        6       10    15     20                                   Nylon-1   20       20       20    20     20                                   mole % MA in        1        1     1      1                                   Terpolymer                                                                    Izod      100      510      535   544    549                                  ______________________________________                                    

                  TABLE 5                                                         ______________________________________                                        POLYBLENDS CONTAINING DIFFERENT NYLONS                                                  Ex 18      Ex 19   Ex 20                                            ______________________________________                                        Nylon-1     45                                                                Nylon-2                  45                                                   Nylon-3                          45                                           ABS-1       50           50      50                                           Terpolymer-1                                                                               5            5       5                                           mole % MA in                                                                               1            1       1                                           Terpolymer                                                                    Izod        850          288     426                                          ______________________________________                                    

We claim:
 1. A polymer blend exhibiting notched Izod impact resistancedetermined in accordance with ASTM D-256-56 of greater than 100 Joulesper meter, said blend consisting of:(A) 5 to 79.5 weight percent of agraft rubber composition comprising copolymer grafted to a rubbersubstrate having a glass transition temperature less than 0° C., whereinsaid copolymer consists of (i) 15 to 55 parts by weight of C₁ to C₄alkyl(meth)acrylate or acrylonitrile monomer and (ii) 85 to 45 parts byweight of tyrene monomer, wherein said graft rubber compositioncomprises 20 to 95 parts by weight to said copolymer and 80 to 5 partsby weight of said rubber; (B) 94.5 to 20 weight percent of a polyamideresin; and (C) 0.5 to 60 weight percent of a compatibilizer polymer ofstyrene monomer, C₁ to C₄ alkyl(meth)acrylate or acrylonitrile monomerand 0.5 to 4 mole percent of a functionalized monomer capable ofreaction with the polyamide resin, wherein the weight percentage ofstyrene monomer in the graft copolymer of component A differs from theweight percentage of styrene monomer in the compatibilizer copolymer ofcomponent C by no more than 5 units; and wherein said percentages ofcomponents A, B and C are based on the total weight of components A, Band C in the blend.
 2. A blend according to claim 1 wherein saidfunctionalized monomer capable of reaction with the polyamide resin is acarboxylic acid, anhydride or ester.
 3. A blend according to claim 2wherein said graft rubber composition comprises a copolymer of styreneand acrylonitrile grafted to a butadiene rubber.
 4. A blend according toclaim 3 wherein said compatibilizer copolymer is a terpolymer ofstyrene, acrylonitrile and maleic anhydride having astyrene:acrylonitrile weight ratio int he range of 80:20 to 50:50.
 5. Ablend according to claim 4 wherein said copolymer of styrene andacrylonitrile grafted to butadiene comprises about 70 to 76 weightpercent styrene.